1 /*
2 * Copyright (c) 2001-2010 Krzysztof Foltman, Markus Schmidt, Thor Harald Johansen, Vladimir Sadovnikov and others
3 * Copyright (c) 2015 Paul B Mahol
4 *
5 * This file is part of FFmpeg.
6 *
7 * FFmpeg is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
11 *
12 * FFmpeg is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
16 *
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with FFmpeg; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20 */
21
22 #include "libavutil/opt.h"
23 #include "libavutil/samplefmt.h"
24 #include "avfilter.h"
25 #include "audio.h"
26 #include "internal.h"
27
28 typedef struct CompensationDelayContext {
29 const AVClass *class;
30 int distance_mm;
31 int distance_cm;
32 int distance_m;
33 double dry, wet;
34 int temp;
35
36 unsigned delay;
37 unsigned w_ptr;
38 unsigned buf_size;
39 AVFrame *delay_frame;
40 } CompensationDelayContext;
41
42 #define OFFSET(x) offsetof(CompensationDelayContext, x)
43 #define A (AV_OPT_FLAG_AUDIO_PARAM|AV_OPT_FLAG_FILTERING_PARAM|AV_OPT_FLAG_RUNTIME_PARAM)
44
45 static const AVOption compensationdelay_options[] = {
46 { "mm", "set mm distance", OFFSET(distance_mm), AV_OPT_TYPE_INT, {.i64=0}, 0, 10, A },
47 { "cm", "set cm distance", OFFSET(distance_cm), AV_OPT_TYPE_INT, {.i64=0}, 0, 100, A },
48 { "m", "set meter distance", OFFSET(distance_m), AV_OPT_TYPE_INT, {.i64=0}, 0, 100, A },
49 { "dry", "set dry amount", OFFSET(dry), AV_OPT_TYPE_DOUBLE, {.dbl=0}, 0, 1, A },
50 { "wet", "set wet amount", OFFSET(wet), AV_OPT_TYPE_DOUBLE, {.dbl=1}, 0, 1, A },
51 { "temp", "set temperature °C", OFFSET(temp), AV_OPT_TYPE_INT, {.i64=20}, -50, 50, A },
52 { NULL }
53 };
54
55 AVFILTER_DEFINE_CLASS(compensationdelay);
56
57 // The maximum distance for options
58 #define COMP_DELAY_MAX_DISTANCE (100.0 * 100.0 + 100.0 * 1.0 + 1.0)
59 // The actual speed of sound in normal conditions
60 #define COMP_DELAY_SOUND_SPEED_KM_H(temp) 1.85325 * (643.95 * sqrt(((temp + 273.15) / 273.15)))
61 #define COMP_DELAY_SOUND_SPEED_CM_S(temp) (COMP_DELAY_SOUND_SPEED_KM_H(temp) * (1000.0 * 100.0) /* cm/km */ / (60.0 * 60.0) /* s/h */)
62 #define COMP_DELAY_SOUND_FRONT_DELAY(temp) (1.0 / COMP_DELAY_SOUND_SPEED_CM_S(temp))
63 // The maximum delay may be reached by this filter
64 #define COMP_DELAY_MAX_DELAY (COMP_DELAY_MAX_DISTANCE * COMP_DELAY_SOUND_FRONT_DELAY(50))
65
config_input(AVFilterLink * inlink)66 static int config_input(AVFilterLink *inlink)
67 {
68 AVFilterContext *ctx = inlink->dst;
69 CompensationDelayContext *s = ctx->priv;
70 unsigned min_size, new_size = 1;
71 int ret;
72
73 s->delay = (s->distance_m * 100. + s->distance_cm * 1. + s->distance_mm * .1) *
74 COMP_DELAY_SOUND_FRONT_DELAY(s->temp) * inlink->sample_rate;
75 min_size = inlink->sample_rate * COMP_DELAY_MAX_DELAY;
76
77 while (new_size < min_size)
78 new_size <<= 1;
79
80 s->delay_frame = av_frame_alloc();
81 if (!s->delay_frame)
82 return AVERROR(ENOMEM);
83
84 s->buf_size = new_size;
85 s->delay_frame->format = inlink->format;
86 s->delay_frame->nb_samples = new_size;
87 #if FF_API_OLD_CHANNEL_LAYOUT
88 FF_DISABLE_DEPRECATION_WARNINGS
89 s->delay_frame->channel_layout = inlink->channel_layout;
90 s->delay_frame->channels = inlink->ch_layout.nb_channels;
91 FF_ENABLE_DEPRECATION_WARNINGS
92 #endif
93 if ((ret = av_channel_layout_copy(&s->delay_frame->ch_layout, &inlink->ch_layout)) < 0)
94 return ret;
95
96 return av_frame_get_buffer(s->delay_frame, 0);
97 }
98
filter_frame(AVFilterLink * inlink,AVFrame * in)99 static int filter_frame(AVFilterLink *inlink, AVFrame *in)
100 {
101 AVFilterContext *ctx = inlink->dst;
102 AVFilterLink *outlink = ctx->outputs[0];
103 CompensationDelayContext *s = ctx->priv;
104 const unsigned b_mask = s->buf_size - 1;
105 const unsigned buf_size = s->buf_size;
106 const unsigned delay = s->delay;
107 const double dry = s->dry;
108 const double wet = s->wet;
109 unsigned r_ptr, w_ptr = 0;
110 AVFrame *out;
111 int n, ch;
112
113 out = ff_get_audio_buffer(outlink, in->nb_samples);
114 if (!out) {
115 av_frame_free(&in);
116 return AVERROR(ENOMEM);
117 }
118 av_frame_copy_props(out, in);
119
120 for (ch = 0; ch < inlink->ch_layout.nb_channels; ch++) {
121 const double *src = (const double *)in->extended_data[ch];
122 double *dst = (double *)out->extended_data[ch];
123 double *buffer = (double *)s->delay_frame->extended_data[ch];
124
125 w_ptr = s->w_ptr;
126 r_ptr = (w_ptr + buf_size - delay) & b_mask;
127
128 for (n = 0; n < in->nb_samples; n++) {
129 const double sample = src[n];
130
131 buffer[w_ptr] = sample;
132 dst[n] = dry * sample + wet * buffer[r_ptr];
133 w_ptr = (w_ptr + 1) & b_mask;
134 r_ptr = (r_ptr + 1) & b_mask;
135 }
136 }
137 s->w_ptr = w_ptr;
138
139 if (ctx->is_disabled) {
140 av_frame_free(&out);
141 return ff_filter_frame(outlink, in);
142 }
143
144 av_frame_free(&in);
145 return ff_filter_frame(outlink, out);
146 }
147
process_command(AVFilterContext * ctx,const char * cmd,const char * args,char * res,int res_len,int flags)148 static int process_command(AVFilterContext *ctx, const char *cmd, const char *args,
149 char *res, int res_len, int flags)
150 {
151 CompensationDelayContext *s = ctx->priv;
152 AVFilterLink *outlink = ctx->outputs[0];
153 int ret;
154
155 ret = ff_filter_process_command(ctx, cmd, args, res, res_len, flags);
156 if (ret < 0)
157 return ret;
158
159 s->delay = (s->distance_m * 100. + s->distance_cm * 1. + s->distance_mm * .1) *
160 COMP_DELAY_SOUND_FRONT_DELAY(s->temp) * outlink->sample_rate;
161
162 return 0;
163 }
164
uninit(AVFilterContext * ctx)165 static av_cold void uninit(AVFilterContext *ctx)
166 {
167 CompensationDelayContext *s = ctx->priv;
168
169 av_frame_free(&s->delay_frame);
170 }
171
172 static const AVFilterPad compensationdelay_inputs[] = {
173 {
174 .name = "default",
175 .type = AVMEDIA_TYPE_AUDIO,
176 .config_props = config_input,
177 .filter_frame = filter_frame,
178 },
179 };
180
181 static const AVFilterPad compensationdelay_outputs[] = {
182 {
183 .name = "default",
184 .type = AVMEDIA_TYPE_AUDIO,
185 },
186 };
187
188 const AVFilter ff_af_compensationdelay = {
189 .name = "compensationdelay",
190 .description = NULL_IF_CONFIG_SMALL("Audio Compensation Delay Line."),
191 .priv_size = sizeof(CompensationDelayContext),
192 .priv_class = &compensationdelay_class,
193 .uninit = uninit,
194 FILTER_INPUTS(compensationdelay_inputs),
195 FILTER_OUTPUTS(compensationdelay_outputs),
196 FILTER_SINGLE_SAMPLEFMT(AV_SAMPLE_FMT_DBLP),
197 .process_command = process_command,
198 .flags = AVFILTER_FLAG_SUPPORT_TIMELINE_INTERNAL,
199 };
200